Facility for confining a pressurized fluid cushion for a ground effect machine

ABSTRACT

A facility for confining pressure fluid cushioning of a groundeffect machine, the facility comprising an endless flexible skirt or wall having a part in double thickness, such part being formed by the placing one above another of two panels which contact one another but which are free relatively to one another to slide on one another when urged by an internal overpressure arising inter alia from meeting an obstacle, the skirt thus being peripherally expanding but skirt wall continuity not being impaired, thanks to the overlapping of the two panels, notwithstanding relative movement thereof.

Elnite tates atet 1 l l 3,713,5e7 Bertin et al. Jan. 30, 1973 541 FACILITY FOR coNFINING A [56] References Cited PRESSURIZED FLUID cIIsIIIoN roa A GROUND-EFFECT MAQHINE UNTED STATES PATENTS 3,252,536 5/l966 Jones ..l80/l28 [75] Inventors: Jean Henri Bertin, Neuilly-sur- Seine; Maurice Paul Bertheot, issy 3,511,331 5/l970 Landry ..l8()/l27 les-Moulineaux; Guy Robert Delamare, Herblay, all of France [73] Assignee: Societe DEtudes El De Developpement Des Aeroglisseurs Marins T0r- [57] 1BSTRACT restres Et Amphibies S.E.-D.A.M., Paris, France Primary Examiner-l (enneth H. Betts Attorney-Stevens, Davis, Miller & Mosher A facility for confining pressure fluid cushioning of a ground-effect machine, the facility comprising an [22] Fil d; A il 28, 1970 endless flexible skirt or wall having a part in double thickness, such part being formed by the placing one above another of two panels which contact one another but which are free relatively to one another to [21] Appl.No.: 32,615

[30] F i A li ti P i it D t slide on one another when urged by an internal overpressure arising inter alia from meeting an obstacle, April 30, France ..69|3944 the Skirt thus being p ip y expanding but Skirt wall continuity not being impaired, thanks to the over- Of the two p notwithstanding relative [51] Int. Cl ..B60v 1/16 movement thereof [58] Field of Search ..180/l27, 128,121

6 Claims, 11 Drawing Figures Pmmznmso Isla 3,713,507

SHEET 3 OF 3 FACILITY FOR CONFINING A PRESSURIZED FLUID CUSHION FOR A GROUND-EFFECT MACHINE This invention, of use for ground-effect machines, relates to a facility for bounding a pressure fluid cushion by means of an endless flexible skirt or wall. When the machine moves. along a machine-supporting surface, a skirt of this kind may encounter obstacles, such as waves in the case of a sea-going vehicle. Upon meeting such an obstacle, the front part of the skirt can readily yield towards the inside of the cushion to pass by the obstacle, but it is difficult for the obstacle to emerge from the cushion because of the strong resistance which the rear part of the skirt opposes to being bent towards the outside of the cushion. The endless wall therefore experiences, more particularly at high speeds, considerable forces which may soon impair the wall. The phenomenon is all the more marked in the case of a skirt which is of a shape flaring towards the rigid structure of the machine, for instance, of frustoconical shape, forthe rear part of a flaredskirt of this kind is inclined towards the cushion interior and so acts as a scoop and tends to pick up the obstacle. This disadvantage has been considered inter alia in U.S. Pat.

No. 3,272,275, which describes means for reducing the a disadvantage.

It is also the object of this invention to obviate this disadvantage and to enable'the obstacle to clear the rearward part of the skirt, but the means according to the invention for this purpose differ radically from the means of the disclosure justflreferred to. 1

According to this invention, the-skirt wall has two panels which are disposed one above another and which can slide on one another and which therefore form a skirt partin double-thickness and peripherally expandable by an intemal-overpressure produced inter alia by an encounter with an obstacle, the two overlapping panels ensuring skirt wall continuity.

Preferably, a facility of this kind isprovided on the rear part of the skirt,(in relation to thenormal direction of .machinemovement) but .canbe repeated at more than one place on the skirt periphery-When stressed in thisgway, the relative sliding of the panelsleads to the outside of the cushion and thus faeilitatingclearance. of theobstaclef I i This invention also uses resilient restoration of the two panels towards their inoperative position relatively to one another in the direction of contraction of the corresponding portion of expanding peripheral skirt. The resilient restoring force can be provided by the actual skirt wall fabric; more advantageously, however, such force is provided by some form of fitted resilient thongs or the like which form a spring.

According to a feature of this invention, resilient thongs of this kind are connected to webbing or strapping-or other reinforcing members secured by stitching or welding or sticking or in some other way to the wall parts to be connected and spreading the mechanical; forces over such parts to prevent excessive local stresses .in the wall material. Preferably, the thongs and webbing are connected through the agency of detachable interconnection members, for ready replacement of the thongs.

corresponding partofthe skirt inclining towardsthe Whatever form of resilient restoration acts on the two panels, the fact that they rub on one another provides a vibration-damping effect which may on its own be sufficient to make it unnecessary to use special dampers co-operating with the resilient restoring force.

The invention is of use in general with any facility for bounding a pressure fluid cushion, but is particularly advantageous when used in the case described in U.S. Pat. No. 3,263,764 of a ground-effect machine comprising a number of independently energized elementary pressure fluid cushions around which a peripheral skirt extends, the same bounding an extra fluid cushion energized by leaks from the inner cushions. The boundary skirts of the extra cushion and of the elementary cushions can in this case be embodied in accordance with the invention with expanding overlapping doublewalled parts.

The following description, taken together with the accompanying exemplary non-limitative drawings, will show clearly how the invention can be carried into effect.

In the drawings: I I v FIG. 1 is a diagrammatic view, in section on the line II.of FIG. 4, of oneembodiment of a ground-effect machine according tothe invention;

FIG. 2 is a view similar to FIG. 1 and showing the detail II of FIG. 1 to an enlarged scale;

FIG. 3 shows a detail concerning the securing of a resilient element to a reinforcing member;

FIG. 4 is a diagrammatic view in section and in elevation on the line IV-IV of FIG. I, showing'the rear of the machinein the case in which there is no obstacle on the path of the machine; i

FIG. 5 is a view similar to FIG. 4 but for the case in which the machine is passing over an obstacle;

FIG. 6 is apartial diagrammatic view. in vertical section on the line Vl-VI of FIG. 4, showing the rear of the machine in the phase of operation shown in FIG. ,4; FIG. Tis a similar view on the lineVIl-VII of FIG.

FIG. 8v is a view similarv to FIG. 2 and showing a constructional variant;

FIG;..9 is a partial diagrammaticperspective view of another variant; r FIG. 10 is a similarview ofanother variant, and

FIG. 11 is a section. on the line XI-XI of FIG. 10.

. Referring to FIGS. 1- 7, a ground-effect machine 1 of which only some of the structure of the frame la is shown .co-operates' with a support surface 2 along which the machine can move in a direction F withthe interposition of-a number of. elementary pressurized fluid cushions 3 bounded by flexible, skirts 4 and having an independent pressure fluid supply. The skirts 4 are flared towards structure Ia and are substantially frustoconical.

A flexible peripheral skirt 5 extends around the elementary cushions 3'and thus bounds afluid cushion 6 supplied by leaks from the cushions 3. Skirt 5 also flares towards structure la and is multi-lobed; its lobes 11 form substantially frusto-conical portions. Bracing members 7 co-operate with theskirt to help the same retain its multi-lobed shape.

Skirt'S has at'the rear two end wall panels 5a, 5b which are in overlapping relationship to seal cushion 6. The resulting overlapping zone at the rear of cushion 6 extends on either side and may or may not be symmetrical of the cushion longitudinal center plane perpendicular to surface 2. Each of the panels 5a, 5b is connected to the body of skirt 5 by resilient straps or thongs or the like 8 which are secured to reinforcing members adapted to distribute the forces, such as strapping or webbing 9 secured by sticking or stitching or stapling or any other means to the parts to be connected.

The thongs 8 are readily removable, to which end, and as can be seen in FIG. 3, the straps 9 terminate in closed rings 90 and the thongs 8 terminate in closed rings 8a, each ring 9a being connected to a corresponding ring 8a by way of a quick-opening loop 10.

While the surface along which the machine moves is free of obstacles, the panels 5a, 5b remain inclined towards the inside of cushion 6 and are located by the thongs 8. If an obstacle such as a wave (shown in chaindotted lines in FIGS. 5 and 7) occurs, it thrusts on those parts of the panels 5a, 5b which are near the surface 2. The panels 5a, 5b are urged rearwardly and slide on one another to take up a position in which they are inclined towards the outside of cushion 6, the thongs 8 elongating. The panels 5a, 5b therefore pass over the obstacle readily, whereafter the resilient thongs 8 return the panels to their initial position. The movements of the panels are damped by their friction on one another.

The dimensions of the overlapping zone of the panels 5a, 5b are such that in their movements the panels continue to overlap and to keep the cushion 6 sealed. Even if the thongs 8 break accidentally, the overlapping panels 5a, 5b still continue to ensure sealing-tightness, thus giving a considerable safety factor. The quickopening loop 10 enables the thongs 8 to be replaced readily.

In the example shown the flexible skirts 4 bounding the cushions 3 are similar to the skirt 5 and, like the latter, have panels 4a, 4b which are disposed in overlying relationship and which overlap and are retained by resilient thongs 8.

Advantageously, the uniform distribution of thongs 8 of the embodiment just described can be replaced by a facility having a resilience which increases downwardly. A facility of this kind is shown in FIG. 8 where there can be seen a trapezoidal arrangement of resilient thongs 8' interposed between strengthening members 9'. Also visible in FIG. 8 is an aperture 12 which is disposed in the skirt inner wall and through which water can pass, thus reducing the coefficient of friction between the overlapping parts.

In the variant shown in FIG. 9, the overlapping panels S'a, 5'!) are of triangular shape and narrow upwardly, leaving at the bottom a substantially triangular aperture 13 which does not disturb the operation of the cushion in practice.

However, if no such aperture is required, the panels can be crossed more to the front, as is the case in FIGS. 10 and 11 where triangular panels 5"a, 5"!) also have along their bottom edges 14 a member resembling a chest expander. Each pane] is vulcanized horizontally along its top edge 15 to the skirt wall which it covers and vertically at the rear, at a place 16, to the skirt wall which it extends.

In this latter embodlment, there are no fitted resilient thongs, the restoring force being provided by making the skirt from a resilient fabric whose resilience is obtained e.g., through the agency of an arrangement of polyester cords l7 inclined to opposite hands at an angle of approximately 45 and therefore crossed, as disclosed bythe assignees U.S. Faure and Arsandaux application Ser. No. 870,543 filed June 10, 1968, now U.S. Pat No. 3,620,325.

We claim:

1. A fluid cushion skirting system for a surface effect machine designed for motion over a rough ground or sea surface having protruding obstacles such as wave crests, comprising a cushion surrounding flexible wall which comprises a wraparound skirt having two separate and distinct end panels lapped over each other with a free interstice therebetween rendering said panels slidable over said free interstice with respect to each other to reduce the degree of overlap thereof upon exertion thereon of outwardly-oriented deflecting forces such as caused by the passage of said obstacles, the degree of overlap of said end panels being large enough in undeflected rest position to maintain some reduced overlap when deflection caused by said obstacles occurs, thereby to allow expansibility of said wall while retaining continuity thereof in the region of said lapped panels, and return means located outside said free interstice for urging said panels back to said degree of overlap in said rest position after passage of said obstacles.

2. Skirting system as claimed in claim 1, wherein said return means comprises resilient tie means bearing on said wall for urging said panels thereof in increasing overlap, said resilient tie means comprising spring means and strap means extending the same and attached to respective wall portions for distributing thereover the resilient action of said spring means.

3. Skirting system as claimed in claim 2, wherein said resilient tie means further comprises a detachable fastener interconnecting said spring means and said strap means,

4. Skirting system as claimed in claim 2, wherein said resilient tie means comprise a succession of elemental ties spaced lengthwise of said skirting system and of increasing resilience from one end tie to the opposite end tie of said succession.

5. Skirting system as claimed in claim 1, further comprising passage means formed through the inner one of said two overlapping panels to put the free interstice therebetween in communication with the cushion inner space bounded by said wall whereby fluid passing therethrough acts as a lubricant for said panels.

6. Skirting system as claimed in claim I, wherein said overlapping panels are of generally triangular tapering shape. 

1. A fluid cushion skirting system for a surface effect machine designed for motion over a rough ground or sea surface having protruding obstacles such as wave crests, comprising a cushion surrounding flexible wall which comprises a wraparound skirt having two separate and distinct end panels lapped over each other with a free interstice therebetween rendering said panels slidable over said free interstice with respect to each other to reduce the degree of overlap thereof upon exertion thereon of outwardly-oriented deflecting forces such as caused by the passage of said obstacles, the degree of overlap of said end panels being large enough in undeflected rest position to maintain some reduced overlap when deflection caused by said obstacles occurs, thereby to allow expansibility of said wall while retaining continuity thereof in the region of said lapped panels, and return means located outside said free interstice for urging said panels back to said degree of overlap in said rest position after passage of said obstacles.
 1. A fluid cushion skirting system for a surface effect machine designed for motion over a rough ground or sea surface having protruding obstacles such as wave crests, comprising a cushion surrounding flexible wall which comprises a wraparound skirt having two separate and distinct end panels lapped over each other with a free interstice therebetween rendering said panels slidable over said free interstice with respect to each other to reduce the degree of overlap thereof upon exertion thereon of outwardly-oriented deflecting forces such as caused by the passage of said obstacles, the degree of overlap of said end panels being large enough in undeflected rest position to maintain some reduced overlap when deflection caused by said obstacles occurs, thereby to allow expansibility of said wall while retaining continuity thereof in the region of said lapped panels, and return means located outside said free interstice for urging said panels back to said degree of overlap in said rest position after passage of said obstacles.
 2. Skirting system as claimed in claim 1, wherein said return means comprises resilient tie means bearing on said wall for urging said panels thereof in increasing overlap, said resilient tie means comprising spring means and strap means extending the same and attached to respective wall portions for distributing thereover the resilient action of said spring means.
 3. Skirting system as claimed in claim 2, wherein said resilient tie means further comprises a detachable fastener interconnecting said spring means and said strap means.
 4. Skirting system as claimed in claim 2, wherein said resilient tie means comprise a succession of elemental ties spaced lengthwise of said skirting system and of increasing resilience from one end tie to the opposite end tie of said succession.
 5. Skirting system as claimed in claim 1, further comprising passage means formed through the inner one of said two overlapping panels to put the free interstice therebetween in communication with the cushion inner space bounded by said wall whereby fluid passing therethrough acts as a lubricant for said panels. 